Sound-on film recording or reproducing apparatus



Dec. 3l, 1935. Hb JOACHlM 2,026,232

SOUND-ON FILM RECORDING OR REPRODUCING APPARATUS Filed Nov. 28, 1934A 2 sheets-sheet 1 Dec. 3l, 1935. v H, JOACHlM l 2,026,232

SOUND-ON FILM RECORDINGy OR REPRODUCIN G APPARATUS Patented Dec. 31, 1935 n i PATENT, oFFICE y amaca SOUND-N FILM RECORDING OR REPRO- DUCING APPARATUS Hermann Joachim, Dresden, Germany, assigner to Zeiss Ikon Aktiengesellschaft, Dresden, Germany Application November 28, 1934, Serial No. '155,084

' In Germany June 30, 1933 s claims. (o1. er1- 2.3)

The present invention relates to the method of photo-electrically recording or reproducing sound by record strips and particularly to the manner of driving the record strip through the recording or reproducing apparatus.

The object of the present invention will be easily understood from the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

For illustrating the invention the principal arrangement is shown in connection with a talkconnected therewith are frictionally driven by ing motion picture projector. However, the invention is equally applicable to a machine for sound recording or reproducing only.

Figure 1 is a view in side elevation of a wellknown form of a motion picture projector having mounted in connection therewith the sound head to which the present invention relates.

Figure 2 shows the same motion picture projector looking from the front the numerals be- 'ing identical to those `of Figure 1-.

Figure 3 is an enlarged detailed view of the sound head per se, showing the interior mechanism.

Figure 4 is, in further detail, a cross sectional view of the driving mechanism of the bearing for the sound head, following line A-B of Figure 3.

For the sake of simplicity and to illustrate more clearly the featuresof the present invention, the projector is shown without the enclosing casing, the supports for the various parts of the apparatus, the light sources etc., the drawings containing only those parts which are most necessary to a clear understanding of the invention.

The motion picture projector I is of a common 40 construction having the film storage reel 2| arand the film vtake-up reel 22 arranged below the mechanism'.

The film is drawn through the gate 3 in a known manner with intermittent movement produced for example by the Geneva movement 3|, the shutter being geared thereto to operate in proper timed relation with the movements of' i the film. The film after having passed the gate 3 runs to the sound reproducing mechanism 4 consisting of the vsound head 4I by which the lrn is supported and moved with a uniform speed. By means of a suitable optical system 42 light from a source, not shown, is focus"ed in a.

' -narrow beam on the `film carrying the sound 55 record, and'v on the opposite side of the film is ranged above the picture and sound mechanism,

the photo-electric cell 43. The modulated output of this cell passes in a known manner through an amplier to a loud speaker 5|.

Sound head 4| is fixed to a shaft 4|U to which the heavy flywheel 4|0| is attached by which construction the necessary constancy of film speed is insured at that point at which the sound record is read oif the lm. This shaft is journalled in a bearing 4|| mounted in the casing |0 of the projector I. This arrangement is well-known and will not be claimed.

Normally 'the sound head and 'the flywheel the film itself.` Only in the beginning when the film starts to pass the projector the shaft 4|0 carrying the sound head 4| and the Vflywheel 4|0I is directly driven by the main drivingmotor 6 of the projector. 'I'his is effected by suitable gears 6|, 62, 63 and a coupling 64 fastened to the shaft 4|0. After the film has attained its normall speed the coupling 64 is broken and the sound head is only driven by the lm itself.

Now it has been found that the flywheel is not at all able to damp out all vibrations transmitted from the driving mechanism to the sound head. 'I'his fact is due to a slight slippage between the fihn and the sound head originating from the friction of the shaft 4||J in the bearing 4| This disadvantage is Wholly avoided by the present invention. It consists in the feature that any friction in the bearing of the shaft 4||l is lessened to a minimum. This can be effected in the best manner by rotating the bearing 4|| in the same sense` and with the same or slightly different speed as the shaft 4|0 rotates.

In working out the chief idea of the present. invention it`has been found that very often the minimum of frictional resistance is effected by driving the bearing 4|| with a speed which is slightly higher than that of the shaft 4|0 which is driven by the film. The difference ismostly very slight.

As experiments have shown,` the speed difference depends on the size of the resistances which influence the speed of the shaft 4|0 in counteraction to the propelling force of the quicker rotating bearing 4||. These counteraction resistances originate, for example, from the air resistance, the stickiness of the nlm, the pressure of rolls pressing the lm against the sound head, etc. It will be easily understood that care must be taken not to drive the bearing 4|| too quickly, otherwise the film instead of driving the sound head would be driven by it thus getting a higher speed at the sound head place than at the film driving sprocket at the gate. 'Ihe result of it would be the fact that thev film and loop normally existing between these both points would soon disappear, the soundhead thus losing its character as a synchronizing4 instrument.

A suitable embodiment of the present'invention is shown in detail in Figures 3 and 4. The sound head shaft 4I0 is journalled in a tubelike bearing 4|| which in its turn is journalled in a bearing 4'I2 which forms a part or is connected to the projector housing I0.

Part 4H also forms an inner bearing for the inner part 64| of a ball coupling 64 the outer part 642 of which is fastened to the sound head shaft 4| 0.

Part 64| carries a gear which meshes with gear 63 fixed to shaft 620 carrying gear 62 meshingY with worm gear 6| fixed on shaft 60.

This shaft` isdriven by the motor 6 and turns over gears 6|, 62, 63, 64| and the coupling 64 the sound head shaft M9. As it is well known the driving connection only exists as long as the inner part 64| of the coupling has a higher speed of rotation than the outer part 642. By

i this arrangement the sound head will be driven different so that bearing 4|| always turns a bit quicker than shaft 4|0.

As already stated the present invention which in the foregoing has been described only on one embodiment is not at all confined to talking motion projectors. 'I'he invention is equally ap- 'plicable to sound reproducers only or to sound recording apparatuswith or without connection rto picture'cameras. Furthermore, the invention may be used for recording, copyingor reproducing sound-on-film regardless of the form in which the sound may be recorded and therefore refers as well to mechanical as to chemical, magnetical or other records placed on a strip which must be driven with highest uniformity of speed through the sound recording or repro-v ducing apparatus.

Therefore what I claim as new and desire to l :secure by Letters Patent of the United States is:

` Vl. In a, device for recording sound on a film or reproducing sound `from a sound film, a drum adapted. to be driven by said film, a shaft on which said drum is secured, arotatary bearing in which said shaft is rotatably supported, and means for rotating said bearing independently of ysaid drum in the same direction in which said drum is driven by the film.

2. In a device for recording sound on a film or reproducing sound from a sound film, a driving mechanism for moving said film, a drum adapted to be driven by the moving film, a shaft on which said drum is secured, a rotatably mounted bearing in which said shaft is rotatably supported, means other than the film itself for coupling said shaft to the driving mechanism during starting and for releasing the said cou- -aoaaassa pling automatically when the drum has attained a speed slightly less than the speed at which it is to be driven by the film, and means for rotating said bearing independently of said drum.

3. In a device for .recording sound on a film 5 or reproducing sound from a sound film, a driving mechanism forv moving said film, a drum adapted to be driven by the moving lm, a shaft on which said drum is secured, a rotatably mounted bearing in which said shaft is rotat- 1| ably supported, means other than the film itself for coupling said shaft to the driving mechanism during starting vand for releaseing the said coupling automatically when the drum has attained a speed slightly less than' the speed at which it is to be driven by thefilm, and means for rotating said bearing independently of said drum, said means being-continuously driven by said driving mechanism.

4. In a device for recording sound on a fihn 21 or reproducing sound from a sound film, a driving mechanism for moving said film, a drum adapted to be driven by the moving film, a shaft on which said drum is secured, a ,rotatably mounted bearing in which said shaft is rotatably 2 supported, means other than the film itself for coupling said shaft to the driving mechanism during lstarting and for releasing the said coupling automatically when the drum has attained a speed slightly less than the film, and means 3 for rotating said bearing independently of said drum, said means being lconnected with said driving mechanism and being adapted to continuously rotate said bearing in the same direction in which the drum is driven by said film. 3

5. In a device for recording sound on a film or reproducing sound from a sound film, a driving mechanism for moving said film, a drum adapted to be driven by the moving film, a shaft on which said drum is secured, a rotatably 4 mounted bearing in which said shaft is rotatably supported, means other than the film itself for coupling said shaft to the driving mechanism during starting and for releasing the said coupling automatically when the drum has attained 4. a speed slightly less than the speed at which it is to be driven by the film, and means for rotating said bearing independently of saiddrum, at a speed varying from the speed at which the drum is driven by the film. y 51 6. In a, device for recording sound on a film or reproducing sound from a sound film, a driving mechanism for moving said film, a drum adapted to be driven by the moving film, a shaft on which said drum -is secured, a, rotatably 5i mounted bearing in which said shaft is rotatably supported, means other than the film itself for coupling said shaft to the driving mechanism during starting and for releasing the said coupling automatically when the drum has attained 6| a speed-slightly less than the speed at which it is to be driven by the film, and means for rotating said bearing independently of said drum, at a speed slightly higher than the speed at which the drum is driven by the film. 65 '7. In a device for recording sound on a lm or reproducing sound from a sound film, a driving mechanism for moving said film, a drum adapted to be driven bythe moving film, a shaft on which said drum is secured, a rotatably mounted 7 bearing in which said shaft is rotatably supported, means otherthan the lm itself for coupling said shaft to the driving mechanism during starting and for releasing the said coupling automatically when the drum has attained 'It a speed'slightiy less than the speed at which it is to be driven by the nlm, and means for rotating said bearing independently ot said drum,

said means being connected withsaid driving mechanism and being adapted to continuously rotate said bearing in thesame direction in -which drum isI driven by said 111m, and at al lmeans for rotating said bearing independently of said drum in the same direction in which scid drumisdrivenbythenimataspeedvarying from the speed of the drum.

9. In a device for recording sound on a nlm or reproducing sound from a sound lm. a drum adaptedtobe driven by said nlm, a shaft on which said 'drum is secured, a rotatable bearing in which said shaft is rotatably supported, and means for rotating said bearing independently ot'sai'd drum in the same direction in which said 10 is ldriven by the nlm, at a speed slightlyl higher than the speed of the drum.

HERMANN JOACHIM. 

